My LCD is now working with the ATMEGA 162 MCU mounted on my
Linefollower2
robot (updated this site with a new picture). First, I
had to disable the JTAGEN fuse on the MCU in order to use
pins PC3 and PC4.

I recently came to the realization that I'm not going to
need these wheel encoders for pure line following, but
that's O.K. - I'd like to use this platform for other uses
as well.

I've been messing around with an LCD display for about 2
weeks now. Had things working on my development board, but
then when I made a PCB, it didn't work. Back to the
development board, worked again. Then when I switched to
directly wiring to he processor on my robot, it stopped
working. When I moved it back to the dev board, still
didn't work. Finally this morning, I found it...

A word to the wise, there is a continuity tester on your
meter - use it whenever you make a new cable.

This weekend I put together a quick hack of a robotics
platform to help a local middle school robotics club learn
to program their OOPic. I am
a little rusty on Basic so we struggled through it together.
The platform had 3 buttons, 2 LEDs and 2 Servos. First I
tested it at home with the Wright Hobbies DEVBOARD.
I demonstrated that the platform worked, then we swapped
the controller board out for the OOPic. All we did was
learn to use the crimping tool to make test leads, get the
LEDs to blink, and then read the pushbuttons to determine
which LEDs to blink. That was enough to fill up 2 hours.

I've got some surface mount components and am trying out
using them. My first attempt was to try to build a parallel
LCD to I2C controller. I got it to work using the devboard,
then I built a board for the ATTINY26 surface mount. I used
solder paste and a toaster
oven to do reflow. The circuit board looks like it got
a little toasty - I probably burnt something inside the
microprocessor. The meter shows that the individual signals
are working, but I haven't been able to get it to properly
control the LCD. I think I will skip the "budget reflow
oven" technique the next time and try just using my
soldering iron.

Seems like others are posting their non-robotics related
stuff, so I thought I'd post that I updated by Georgia
Hot Boiled Peanuts web page. It is getting pretty long!
I'm thinking of breaking it down into multiple pages.

Halloween
has come and gone. My plans were not fully realized, and I
didn't get the mechanical part sorted out (had problems with
the controller attached to the wireless receiver.) But I
did get several compliments, such as, "Your house is
SCARY!". I have some updated photos.

I had a busy weekend. Mike Lynch fwded me a Halloween
project for making eerie flickering candles out of LEDs.
Steve Karg brought lots of surplus bright green LEDs to one
of the meetings and this is a great application for th em.
The outline of a Faux Candles project is available as a PDF
file from: Parallax
EFX.

I also worked on getting a wiper motor hooked up to a rope
to make a moving figure. The 1 1/2" pulleys made it move
slowly. I used a 4" clothesline pulley and it runs at
a great speed to make a halloween spook. I need some way to
make sure the pully is fed to the motor so it doesn't jump
the track so often (about one time out of 3 at the moment)
I used wires around the rope as a safety catch to make sure
no one gets hurt.

So here is the planned Halloween setup:

Line the driveway with halloween lights from target.

At the end of the halloween lights, setup the gemmy toys
motion activated Beware
sign from Target.

We have some low voltage lights that line part of the
sidewalk. Leave those on for safety.

After that, the 7 faux candles will line the rest of
the sidewalk and steps.

A proximity sensor near the start of the faux candles
will trip and setup an eerie pattern with the lights, then
activeate the spook on the rope with a remote control.

This morning I gave a short presentation to the Belmont
Hills "Booming Bears"
First Lego League team on the topic of "Design" and
showed them some sample drawings and some techniques. They
have their playing field all assembled (except for the boat)
and have built a motor operated arm for one of the
challenges already! I made a poster of Keith Rowell's
awesome little Knewt
robot to illustrate the evolution of a design. I also
dropped off some graph paper, photo paper, 2H pencils for
drawing, and a shoebox full of extra legos. They were all
studying the Lego ROBOBuilder software for programming their
robot.

Last night's AHRC
Robot Builder's night out was terriffic. There was a good
crowd with enough experienced folks there to help out some
of us less experienced folks. Not only that, but the
Norcross High Georgia BEST
team was working on their project, which was pretty cool (a
simulation of repairing the Hubble with a teleoperated
robot.) I was blown away by the differnt types of equipment
they had (CNC Lathes and milling machines, plastic injection
moulding, even a wind tunnel!)

My mission for the night was to work on a drive train for my
larger robot. I want to build a standard 2 wheel
differrential drive train, and need to some how connect my
motor w/ a
5/16" threaded shaft to a wheel with a 1/2" bore -
preferably by using some pulleys to create a belt drive that
would slip if the wheel stalls. Some folks were more
interested in seeing what was going on inside the wiper
motor, so we pulled the cover off and peeked inside the coils.

I had 1/4" vacuum cleaner belts and some pulleys I bought at
the hardware store. 2x plastic 2" pulleys for clotheslines and a
double metal pulley 1 1/2" dia all with 1/4" bore. I had
some 1/4" and 1/2" shafts as well. Luckily, Mike Lynch was
there and helped out a lot. We used the chop saw to cut
some axles from my 1/2" metal rod, and we were able to
remove the 1/4" bearing from the metal pulleys by just
pressing them out with a vise and some hex sockets, which
left us with 1/2" pulleys! We used hex couplers on the
5/16" thread from the motor which also fits the 1/2" bore
of the pulleys with the bearings removed.

The pulleys had no hubs, but we drilled and tapped into the
middle of the pulley for a 6-32 set screw. I'm advised to
use lots of epoxy on the hex coupler to pulley setup, and
some lock-tite on the threads of the set screws and the
motor threads that connect to the hex coupler.

Don't you hate it when someone asks you what your robot is
going to do? In my case, I have no real idea what I want
it to do. I will be thrilled if I can get it to move into a
straight line and not run into a wall at high speed.
I'll have to make a new webpage for my this larger robot and
post it on my projects
webpage soon. That is, as soon as I can figure out
what this robot is going to "do".

Building a little RS-232 to TTL line level converter
board w/ a MAX232 chip.

Wired up the first serial port on the Atmel AT MEGA 162
and put in some test code to read and write from the port.

As far as making the rs232 line level converter: A word to
the wise, check out Al Williams' web site AWC for a cheap and easy way
out. But I was halfway done with my version before I found
it. Since I wanted this to be fairly sturdy so I could
re-use it for multiple robots, I made a schematic in Eagle and etched a PCB for
it. My first board was a flop. Several of the traces had
bridges because I didn't scrub all the paper off, and I
accidentally mirrored the image to boot. The second board
came out
of the etching process much better after using a toothbrush
to scrub the smaller bits of paper off. But I didn't align the board and
the drawing very well for my 2 layer design. And I crossed
RX and TX. And I didn't wire up the power pin. And, well,
it was pretty much the worst pcb I've ever made, but it does
work. Because I didn't plan ahead on putting it in a
particular project box, it won't fit in a project box, so I
just sprayed the bottom side with clear
enamel to prevent shorts and am using it as-is.

Next on my plate for the linefollower is to get it to drive
in a straight line. I can work on my motor controller logic
(a PID loop, I guess) now that I have the encoders installed
and a serial port for debugging.

Tonight I'm off to the AHRC Robot builder's
night out. I've got my eye on making a drivetrain for the
wiper motors for building some kind of larger size bot.

My new
linefollower project is coming along nicely. Now the
family is back, but I've got my project board w/ an
ATMEGA162 MCU and HBridge wired up which is controlling both
motors now.

I put the robot on the floor for a little test run (no wheel
encoders yet.) Overall I was pretty pleased with the flat
out speed of the bot and the ability to control speed of the
motors w/ locked anti-phase PWM. But I can see that there
are some issues:

The wheels quickly lose traction on the painted
concrete floor of my basement.

The rear wheel doesn't turn and influences the
direction of the robot (especially in reverse!)

The batteries are mounted toward the back of the bot. I
probably need to move the over the front wheels to help with
differential drive. I may need to replace the wheels with
wheels of larger diameter (Currently about 1 1/2" in
diameter, maybe go up to 2 1/2".)

The family is out of town, so I am working on robots
while not out winning bread. To build a big bot with the
wiper motors I'm going to need some more complex mechanics
- starting with a coupler for the motor to wheels. I was
going to use pulleys, but can't find anything remotely
suitable at the local hardware store, so I might just
have to make something myself. I can get access to a
machine shop at the next AHRC RBNO, or at least some
access to some good advice.

I was out and about this weekend and stopped in Hobby Town
and picked up a pair of Tamiya gear boxes. Then it hit me -
I could quickly build a little robot. So, I decided to go
for another stab at a line
follower. There was some discussion on the AHRC
mailing list regarding locked anti-phase PWM which I put
into action.